"Exxon Mobil was working to clean up thousands of barrels of oil in Mayflower, Arkansas, after a pipeline carrying heavy Canadian crude ruptured, a major spill likely to stoke debate over transporting Canada's oil to the United States."

"Exxon shut the Pegasus pipeline, which can carry more than 90,000 barrels per day (bpd) of crude oil from Pakota, Illinois, to Nederland, Texas, after the leak was discovered on Friday afternoon, the company said in a statement.

Exxon, hit with a $1.7 million fine by regulators this week over a 2011 spill in the Yellowstone River, said a few thousand barrels of oil had been observed."